{"gene":"PLEK2","run_date":"2026-06-10T06:43:35","timeline":{"discoveries":[{"year":2019,"finding":"PLEK2 directly interacts with the kinase domain of EGFR (shown by mass spectrometry and co-immunoprecipitation) and suppresses EGFR ubiquitination mediated by c-CBL, leading to constitutive activation of EGFR signaling in gallbladder cancer cells.","method":"Mass spectrometry, co-immunoprecipitation, ubiquitination assay","journal":"Journal of experimental & clinical cancer research : CR","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP and mass spectrometry in single lab, two orthogonal methods supporting interaction and ubiquitination suppression","pmids":["31182136"],"is_preprint":false},{"year":2019,"finding":"PLEK2 directly interacts with SHIP2 and targets it for ubiquitin-dependent degradation in non-small cell lung cancer cells, thereby activating TGF-β/PI3K/AKT signaling and promoting EMT, migration, and vascular invasion.","method":"Co-immunoprecipitation, ubiquitination assay, western blot, overexpression/knockdown functional assays","journal":"International journal of cancer","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP plus ubiquitination assay in single lab, two orthogonal methods","pmids":["31498891"],"is_preprint":false},{"year":2019,"finding":"PLEK2 promotes gallbladder cancer cell migration, invasion, and liver metastasis via regulation of the epithelial-mesenchymal transition (EMT) process, with downstream activation of CCL2 as a motility-promoting effector downstream of PLEK2/EGFR signaling.","method":"RNA-sequencing, qRT-PCR, functional migration/invasion assays, mouse metastasis model","journal":"Journal of experimental & clinical cancer research : CR","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — RNA-seq plus functional cellular and in vivo assays, single lab","pmids":["31182136"],"is_preprint":false},{"year":2021,"finding":"TGF-β stimulates Smad2/3 binding to the PLEK2 promoter to induce PLEK2 expression in oesophageal squamous cell carcinoma, as demonstrated by luciferase reporter and chromatin immunoprecipitation assays.","method":"Luciferase reporter assay, chromatin immunoprecipitation (ChIP)","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — two orthogonal methods (luciferase + ChIP) in single lab establishing direct transcriptional regulation","pmids":["34601488"],"is_preprint":false},{"year":2021,"finding":"PLEK2 regulates LCN2 expression downstream in oesophageal squamous cell carcinoma; LCN2 overexpression rescues migration and invasion inhibited by PLEK2 knockdown, and AKT phosphorylation is activated throughout this regulatory axis.","method":"RNA-seq, knockdown/overexpression rescue experiments, western blot","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis by rescue experiment plus RNA-seq, single lab","pmids":["34601488"],"is_preprint":false},{"year":2021,"finding":"PLEK2 knockdown suppresses PI3K/AKT/mTOR pathway activity in osteosarcoma cells, as verified by western blot, establishing PLEK2 as an upstream activator of this signaling pathway in osteosarcoma.","method":"Bioinformatics analysis, western blot, knockdown functional assays, in vivo xenograft","journal":"Oncology letters","confidence":"Low","confidence_rationale":"Tier 3 / Weak — western blot pathway readout after knockdown, single lab, single method for pathway placement","pmids":["34084215"],"is_preprint":false},{"year":2022,"finding":"PLEK2 interacts with c-Myc protein and reduces the association of FBXW7 with c-Myc, thereby preventing ubiquitin-mediated proteasomal degradation of c-Myc in head and neck squamous cell carcinoma; furthermore, c-Myc directly binds the PLEK2 promoter and activates its transcription, forming a positive feedback loop.","method":"Co-immunoprecipitation, cycloheximide chase analysis, ubiquitination assay, ChIP-qPCR, luciferase reporter assay, rescue experiments","journal":"Cancer communications (London, England)","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — multiple orthogonal methods (Co-IP, ubiquitination assay, cycloheximide chase, ChIP, luciferase) in a single rigorous study establishing both interaction and regulatory loop","pmids":["36002342"],"is_preprint":false},{"year":2022,"finding":"BRD4 binds to the promoter region of the PLEK2 gene and transcriptionally activates PLEK2 expression in non-small cell lung cancer, as demonstrated by chromatin immunoprecipitation; suppression of BRD4 by siRNA or JQ-1 inhibits NSCLC proliferation and migration downstream of PLEK2/PI3K/AKT signaling.","method":"Chromatin immunoprecipitation, western blot, siRNA knockdown, JQ-1 pharmacological inhibition, functional assays","journal":"Molecular biology reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP plus functional knockdown with two orthogonal perturbations (siRNA + JQ-1), single lab","pmids":["35122599"],"is_preprint":false},{"year":2022,"finding":"CRISPR/Cas9 knockout of PIK3CD (p110δ) in GBM cells dramatically reduces PLEK2 expression (along with PAK3), placing PLEK2 downstream of PIK3CD in a pathway controlling glioma cell migration, invasion, and colony formation.","method":"CRISPR/Cas9 knockout, RT2 profiler PCR array, RNAseq, functional migration/invasion assays, in vivo tumorigenesis","journal":"Laboratory investigation","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis by complete KO with multiple functional readouts, single lab","pmids":["35851857"],"is_preprint":false},{"year":2023,"finding":"α5-nAChR mediates nicotine-induced PLEK2 expression via STAT3 signaling in lung adenocarcinoma, and PLEK2 in turn directly interacts with CFL1 (cofilin-1) to mediate cytoskeletal remodeling and EMT in nicotine-induced cancer progression.","method":"Co-immunoprecipitation, in vivo xenograft validation, human tissue immunostaining, functional migration/invasion assays","journal":"Molecular carcinogenesis","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP for interaction plus pathway epistasis, validated in xenograft and human tissues, single lab","pmids":["37921560"],"is_preprint":false},{"year":2024,"finding":"PLEK2 directly interacts with SPC25 (shown by co-immunoprecipitation) in lung adenocarcinoma cells, and this interaction is associated with PI3K/AKT signaling activation required for PLEK2-induced proliferation and migration.","method":"Gene expression profiling, co-immunoprecipitation, knockdown functional assays, in vivo xenograft","journal":"Cell biology international","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single Co-IP for interaction, single lab, limited mechanistic follow-up of the PLEK2–SPC25 complex","pmids":["38894536"],"is_preprint":false},{"year":2023,"finding":"PLEK2 knockdown in gastric cancer cells reduces PD-L1 expression and promotes apoptosis; hyperthermia treatment downregulates both PLEK2 and PD-L1, partially reversing IFNγ suppression in co-cultured activated T cells.","method":"Gene knockdown (siRNA), western blot, RT-qPCR, flow cytometry, T cell co-culture assay","journal":"Gene","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single-lab knockdown study with functional readouts but no direct biochemical mechanism linking PLEK2 to PD-L1 regulation","pmids":["38147897"],"is_preprint":false},{"year":2024,"finding":"PLEK2 promotes migration and invasion in pancreatic ductal adenocarcinoma by activating MMP1 expression and p-ERK and p-STAT3 signaling through the IL-17 pathway, as identified by RNA-seq and verified by western blot.","method":"RNA-seq, western blot, wound healing and transwell assays, in vivo xenograft, knockdown","journal":"Molecular and cellular biochemistry","confidence":"Low","confidence_rationale":"Tier 3 / Weak — RNA-seq pathway identification plus western blot verification, single lab, no direct biochemical mechanism for PLEK2–MMP1 link","pmids":["39117976"],"is_preprint":false}],"current_model":"PLEK2 (Pleckstrin-2) functions as an oncogenic scaffolding/adaptor protein that promotes cancer cell migration, invasion, and EMT through multiple mechanisms: it interacts with and protects EGFR from c-CBL-mediated ubiquitination to sustain EGFR signaling, targets SHIP2 for ubiquitin-dependent degradation to activate PI3K/AKT signaling, interacts with c-Myc to shield it from FBXW7-mediated proteasomal degradation (while c-Myc reciprocally transcribes PLEK2 in a positive feedback loop), and interacts with cofilin-1 (CFL1) to remodel the cytoskeleton; upstream, PLEK2 transcription is activated by TGF-β/Smad2/3, BRD4, ELK1, and α5-nAChR/STAT3, and PLEK2 acts downstream of PIK3CD in glioblastoma."},"narrative":{"mechanistic_narrative":"PLEK2 is an oncogenic scaffolding/adaptor protein that drives cancer cell migration, invasion, and epithelial-mesenchymal transition across multiple solid tumor types [PMID:31498891, PMID:31182136]. It operates largely by controlling the stability and activity of signaling proteins through ubiquitination-dependent mechanisms: it binds the kinase domain of EGFR and shields it from c-CBL-mediated ubiquitination to sustain EGFR signaling [PMID:31182136], and it interacts with SHIP2 to target it for ubiquitin-dependent degradation, thereby relieving inhibition of PI3K/AKT signaling and promoting EMT and invasion [PMID:31498891]. PLEK2 also binds c-Myc and displaces FBXW7, preventing proteasomal degradation of c-Myc, while c-Myc reciprocally activates PLEK2 transcription to form a positive feedback loop [PMID:36002342]. Convergence on PI3K/AKT signaling is a recurring theme downstream of PLEK2 [PMID:31498891, PMID:35122599]. PLEK2 additionally interacts with cofilin-1 (CFL1) to remodel the cytoskeleton during nicotine-induced cancer progression [PMID:37921560]. PLEK2 transcription is induced by upstream regulators including TGF-β/Smad2/3 [PMID:34601488], BRD4 [PMID:35122599], and α5-nAChR/STAT3 signaling [PMID:37921560], and PLEK2 lies downstream of PIK3CD in glioma [PMID:35851857]. Downstream effectors mediating its motility phenotypes include CCL2 [PMID:31182136] and LCN2 [PMID:34601488].","teleology":[{"year":2019,"claim":"Established a first biochemical mechanism for PLEK2 oncogenicity by showing it physically protects a receptor tyrosine kinase from degradation, explaining sustained pro-migratory signaling.","evidence":"Mass spectrometry, reciprocal Co-IP, and ubiquitination assays in gallbladder cancer cells, with RNA-seq and a mouse metastasis model identifying CCL2 as a downstream effector","pmids":["31182136"],"confidence":"Medium","gaps":["Does not define the structural basis of the PLEK2-EGFR kinase domain interaction","Does not establish whether PLEK2 competes with c-CBL directly or acts allosterically","CCL2 induction linked correlatively to EGFR signaling, not by direct biochemical step"]},{"year":2019,"claim":"Showed PLEK2 can also act as a destabilizer rather than a stabilizer, targeting the lipid phosphatase SHIP2 for degradation to activate PI3K/AKT and drive EMT.","evidence":"Co-IP, ubiquitination assays, and overexpression/knockdown functional assays in NSCLC cells","pmids":["31498891"],"confidence":"Medium","gaps":["Does not identify the E3 ligase PLEK2 recruits to SHIP2","Does not reconcile how PLEK2 protects EGFR yet degrades SHIP2 mechanistically"]},{"year":2021,"claim":"Identified the upstream transcriptional driver of PLEK2, placing it within the TGF-β signaling axis, and defined a downstream effector for its motility phenotype.","evidence":"Luciferase reporter and ChIP assays for Smad2/3 promoter binding, plus RNA-seq and rescue experiments identifying LCN2 in oesophageal squamous cell carcinoma","pmids":["34601488"],"confidence":"Medium","gaps":["Does not link Smad2/3 induction of PLEK2 to a specific protein-level mechanism","Mechanism connecting PLEK2 to LCN2 expression not defined"]},{"year":2021,"claim":"Reinforced PLEK2 as an upstream activator of PI3K/AKT/mTOR signaling in a distinct tumor context.","evidence":"Knockdown with western blot pathway readout and xenograft in osteosarcoma cells","pmids":["34084215"],"confidence":"Low","gaps":["Single western-blot pathway readout for pathway placement","No direct biochemical mechanism linking PLEK2 to PI3K/AKT in this context"]},{"year":2022,"claim":"Provided the most rigorous mechanism: PLEK2 stabilizes the oncogenic transcription factor c-Myc by blocking FBXW7 access, and c-Myc reciprocally transcribes PLEK2, establishing a self-amplifying feed-forward loop.","evidence":"Co-IP, cycloheximide chase, ubiquitination assays, ChIP-qPCR, and luciferase reporter assays in head and neck squamous cell carcinoma","pmids":["36002342"],"confidence":"High","gaps":["Does not map the PLEK2 region required for c-Myc binding or FBXW7 displacement","Does not quantify the contribution of the feedback loop to tumor maintenance in vivo"]},{"year":2022,"claim":"Added a second transcriptional activator, BRD4, linking epigenetic readers to PLEK2 expression and its downstream PI3K/AKT axis.","evidence":"ChIP, siRNA and JQ-1 pharmacological inhibition with functional assays in NSCLC","pmids":["35122599"],"confidence":"Medium","gaps":["Does not establish whether BRD4 acts directly or via intermediary transcription factors","PI3K/AKT placement downstream of PLEK2 inferred from pathway readout"]},{"year":2022,"claim":"Placed PLEK2 genetically downstream of PIK3CD (p110δ), connecting it to a defined PI3K isoform-driven migration program in glioma.","evidence":"CRISPR/Cas9 knockout of PIK3CD with profiler PCR array, RNA-seq, and functional/in vivo assays in GBM cells","pmids":["35851857"],"confidence":"Medium","gaps":["Does not establish whether PIK3CD regulates PLEK2 transcriptionally or post-transcriptionally","Direct biochemical link absent"]},{"year":2023,"claim":"Connected PLEK2 to cytoskeletal remodeling through a direct interaction with cofilin-1, and embedded it in a nicotine/α5-nAChR/STAT3 induction pathway.","evidence":"Co-IP, xenograft, human tissue immunostaining, and functional assays in lung adenocarcinoma","pmids":["37921560"],"confidence":"Medium","gaps":["Does not define how PLEK2-CFL1 binding alters cofilin activity","Single Co-IP without reciprocal mapping of interaction interface"]},{"year":2023,"claim":"Extended PLEK2 function to immune evasion by linking it to PD-L1 expression and T-cell suppression in gastric cancer.","evidence":"siRNA knockdown, western blot, flow cytometry, and T-cell co-culture with hyperthermia treatment","pmids":["38147897"],"confidence":"Low","gaps":["No direct biochemical mechanism linking PLEK2 to PD-L1 regulation","Correlation between PLEK2 and PD-L1 not mechanistically resolved"]},{"year":2024,"claim":"Reported additional candidate partners and effectors broadening the PLEK2 interaction and signaling repertoire.","evidence":"Co-IP with SPC25 in lung adenocarcinoma (PMID 38894536) and RNA-seq/western blot linking PLEK2 to MMP1 via IL-17/ERK/STAT3 in PDAC (PMID 39117976)","pmids":["38894536","39117976"],"confidence":"Low","gaps":["Single Co-IP for the PLEK2-SPC25 interaction without reciprocal validation","No direct biochemical mechanism for the PLEK2-MMP1 link"]},{"year":null,"claim":"How a single adaptor reconciles opposing activities (stabilizing EGFR and c-Myc while degrading SHIP2) and what its structural determinants of partner selection are remain unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No structural model of PLEK2 or its interaction interfaces","E3 ligase machinery PLEK2 recruits to SHIP2 unidentified","Whether PLEK2's pleckstrin-homology lipid binding contributes to membrane signaling untested in this corpus"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,1,6]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[0,1,6]},{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[9]}],"localization":[],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,1,6]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[1,6]},{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[3,6,7]}],"complexes":[],"partners":["EGFR","SHIP2","MYC","FBXW7","CFL1","SPC25"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9NYT0","full_name":"Pleckstrin-2","aliases":[],"length_aa":353,"mass_kda":40.0,"function":"May help orchestrate cytoskeletal arrangement. Contribute to lamellipodia formation","subcellular_location":"Cell projection, lamellipodium membrane; Cytoplasm, cytoskeleton","url":"https://www.uniprot.org/uniprotkb/Q9NYT0/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/PLEK2","classification":"Not Classified","n_dependent_lines":4,"n_total_lines":1208,"dependency_fraction":0.0033112582781456954},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/PLEK2","total_profiled":1310},"omim":[{"mim_id":"608007","title":"PLECKSTRIN 2; PLEK2","url":"https://www.omim.org/entry/608007"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Uncertain","locations":[{"location":"Vesicles","reliability":"Uncertain"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"adrenal gland","ntpm":48.7}],"url":"https://www.proteinatlas.org/search/PLEK2"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"Q9NYT0","domains":[{"cath_id":"2.30.29.30","chopping":"6-120","consensus_level":"high","plddt":87.9746,"start":6,"end":120},{"cath_id":"1.10.10.10","chopping":"130-227","consensus_level":"high","plddt":88.3385,"start":130,"end":227},{"cath_id":"2.30.29.30","chopping":"240-352","consensus_level":"high","plddt":86.1967,"start":240,"end":352}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9NYT0","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9NYT0-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9NYT0-F1-predicted_aligned_error_v6.png","plddt_mean":85.69},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=PLEK2","jax_strain_url":"https://www.jax.org/strain/search?query=PLEK2"},"sequence":{"accession":"Q9NYT0","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9NYT0.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9NYT0/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9NYT0"}},"corpus_meta":[{"pmid":"31182136","id":"PMC_31182136","title":"PLEK2 promotes gallbladder cancer invasion and metastasis through EGFR/CCL2 pathway.","date":"2019","source":"Journal of experimental & clinical cancer research : CR","url":"https://pubmed.ncbi.nlm.nih.gov/31182136","citation_count":85,"is_preprint":false},{"pmid":"31498891","id":"PMC_31498891","title":"PLEK2 mediates metastasis and vascular invasion via the ubiquitin-dependent degradation of SHIP2 in non-small cell lung cancer.","date":"2019","source":"International journal of cancer","url":"https://pubmed.ncbi.nlm.nih.gov/31498891","citation_count":55,"is_preprint":false},{"pmid":"21698244","id":"PMC_21698244","title":"Transcriptome profiling of whole blood cells identifies PLEK2 and C1QB in human melanoma.","date":"2011","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/21698244","citation_count":40,"is_preprint":false},{"pmid":"36002342","id":"PMC_36002342","title":"PLEK2 promotes cancer stemness and tumorigenesis of head and neck squamous cell carcinoma via the c-Myc-mediated positive feedback loop.","date":"2022","source":"Cancer communications (London, England)","url":"https://pubmed.ncbi.nlm.nih.gov/36002342","citation_count":32,"is_preprint":false},{"pmid":"34601488","id":"PMC_34601488","title":"TGF-β-induced PLEK2 promotes metastasis and chemoresistance in oesophageal squamous cell carcinoma by regulating LCN2.","date":"2021","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/34601488","citation_count":27,"is_preprint":false},{"pmid":"34084215","id":"PMC_34084215","title":"PLEK2 promotes osteosarcoma tumorigenesis and metastasis by activating the PI3K/AKT signaling pathway.","date":"2021","source":"Oncology letters","url":"https://pubmed.ncbi.nlm.nih.gov/34084215","citation_count":18,"is_preprint":false},{"pmid":"34204789","id":"PMC_34204789","title":"PLEK2, RRM2, GCSH: A Novel WWOX-Dependent Biomarker Triad of Glioblastoma at the Crossroads of Cytoskeleton Reorganization and Metabolism Alterations.","date":"2021","source":"Cancers","url":"https://pubmed.ncbi.nlm.nih.gov/34204789","citation_count":17,"is_preprint":false},{"pmid":"36121452","id":"PMC_36121452","title":"PLEK2 and IFI6, representing mesenchymal and immune-suppressive microenvironment, predicts resistance to neoadjuvant immunotherapy in esophageal squamous cell carcinoma.","date":"2022","source":"Cancer immunology, immunotherapy : CII","url":"https://pubmed.ncbi.nlm.nih.gov/36121452","citation_count":16,"is_preprint":false},{"pmid":"35851857","id":"PMC_35851857","title":"Oncogenic potential of PIK3CD in glioblastoma is exerted through cytoskeletal proteins PAK3 and PLEK2.","date":"2022","source":"Laboratory investigation; a journal of technical methods and pathology","url":"https://pubmed.ncbi.nlm.nih.gov/35851857","citation_count":15,"is_preprint":false},{"pmid":"38894536","id":"PMC_38894536","title":"PLEK2 activates the PI3K/AKT signaling pathway to drive lung adenocarcinoma progression by upregulating SPC25.","date":"2024","source":"Cell biology international","url":"https://pubmed.ncbi.nlm.nih.gov/38894536","citation_count":11,"is_preprint":false},{"pmid":"35122599","id":"PMC_35122599","title":"PLEK2 promotes the proliferation and migration of non-small cell lung cancer cells in a BRD4-dependent manner.","date":"2022","source":"Molecular biology reports","url":"https://pubmed.ncbi.nlm.nih.gov/35122599","citation_count":10,"is_preprint":false},{"pmid":"37921560","id":"PMC_37921560","title":"PLEK2 mediates metastasis and invasion via α5-nAChR activation in nicotine-induced lung adenocarcinoma.","date":"2023","source":"Molecular carcinogenesis","url":"https://pubmed.ncbi.nlm.nih.gov/37921560","citation_count":7,"is_preprint":false},{"pmid":"39117976","id":"PMC_39117976","title":"PLEK2 promotes migration and invasion in pancreatic ductal adenocarcinoma by MMP1 through IL-17 pathway.","date":"2024","source":"Molecular and cellular biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/39117976","citation_count":2,"is_preprint":false},{"pmid":"38147897","id":"PMC_38147897","title":"Hyperthermia inhibits the progression of gastric cancer by downregulating PLEK2/PD-L1 and possibly participates in immunomodulation.","date":"2023","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/38147897","citation_count":2,"is_preprint":false},{"pmid":"39957592","id":"PMC_39957592","title":"CircCNKSR2 Facilitates NSCLC Tumorigenesis and Warburg Effect via miRNA-138-5p/PLEK2 Axis.","date":"2025","source":"Critical reviews in eukaryotic gene expression","url":"https://pubmed.ncbi.nlm.nih.gov/39957592","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":10347,"output_tokens":2985,"usd":0.037908,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":10386,"output_tokens":3675,"usd":0.071902,"stage2_stop_reason":"end_turn"},"total_usd":0.10981,"stage1_batch_id":"msgbatch_01CNoDbkChHEkgrJnL7BwtGJ","stage2_batch_id":"msgbatch_016Y4x9E9Wg5VQDANj9quSQD","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2019,\n      \"finding\": \"PLEK2 directly interacts with the kinase domain of EGFR (shown by mass spectrometry and co-immunoprecipitation) and suppresses EGFR ubiquitination mediated by c-CBL, leading to constitutive activation of EGFR signaling in gallbladder cancer cells.\",\n      \"method\": \"Mass spectrometry, co-immunoprecipitation, ubiquitination assay\",\n      \"journal\": \"Journal of experimental & clinical cancer research : CR\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP and mass spectrometry in single lab, two orthogonal methods supporting interaction and ubiquitination suppression\",\n      \"pmids\": [\"31182136\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"PLEK2 directly interacts with SHIP2 and targets it for ubiquitin-dependent degradation in non-small cell lung cancer cells, thereby activating TGF-β/PI3K/AKT signaling and promoting EMT, migration, and vascular invasion.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assay, western blot, overexpression/knockdown functional assays\",\n      \"journal\": \"International journal of cancer\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP plus ubiquitination assay in single lab, two orthogonal methods\",\n      \"pmids\": [\"31498891\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"PLEK2 promotes gallbladder cancer cell migration, invasion, and liver metastasis via regulation of the epithelial-mesenchymal transition (EMT) process, with downstream activation of CCL2 as a motility-promoting effector downstream of PLEK2/EGFR signaling.\",\n      \"method\": \"RNA-sequencing, qRT-PCR, functional migration/invasion assays, mouse metastasis model\",\n      \"journal\": \"Journal of experimental & clinical cancer research : CR\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — RNA-seq plus functional cellular and in vivo assays, single lab\",\n      \"pmids\": [\"31182136\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"TGF-β stimulates Smad2/3 binding to the PLEK2 promoter to induce PLEK2 expression in oesophageal squamous cell carcinoma, as demonstrated by luciferase reporter and chromatin immunoprecipitation assays.\",\n      \"method\": \"Luciferase reporter assay, chromatin immunoprecipitation (ChIP)\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — two orthogonal methods (luciferase + ChIP) in single lab establishing direct transcriptional regulation\",\n      \"pmids\": [\"34601488\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"PLEK2 regulates LCN2 expression downstream in oesophageal squamous cell carcinoma; LCN2 overexpression rescues migration and invasion inhibited by PLEK2 knockdown, and AKT phosphorylation is activated throughout this regulatory axis.\",\n      \"method\": \"RNA-seq, knockdown/overexpression rescue experiments, western blot\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis by rescue experiment plus RNA-seq, single lab\",\n      \"pmids\": [\"34601488\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"PLEK2 knockdown suppresses PI3K/AKT/mTOR pathway activity in osteosarcoma cells, as verified by western blot, establishing PLEK2 as an upstream activator of this signaling pathway in osteosarcoma.\",\n      \"method\": \"Bioinformatics analysis, western blot, knockdown functional assays, in vivo xenograft\",\n      \"journal\": \"Oncology letters\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — western blot pathway readout after knockdown, single lab, single method for pathway placement\",\n      \"pmids\": [\"34084215\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"PLEK2 interacts with c-Myc protein and reduces the association of FBXW7 with c-Myc, thereby preventing ubiquitin-mediated proteasomal degradation of c-Myc in head and neck squamous cell carcinoma; furthermore, c-Myc directly binds the PLEK2 promoter and activates its transcription, forming a positive feedback loop.\",\n      \"method\": \"Co-immunoprecipitation, cycloheximide chase analysis, ubiquitination assay, ChIP-qPCR, luciferase reporter assay, rescue experiments\",\n      \"journal\": \"Cancer communications (London, England)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — multiple orthogonal methods (Co-IP, ubiquitination assay, cycloheximide chase, ChIP, luciferase) in a single rigorous study establishing both interaction and regulatory loop\",\n      \"pmids\": [\"36002342\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"BRD4 binds to the promoter region of the PLEK2 gene and transcriptionally activates PLEK2 expression in non-small cell lung cancer, as demonstrated by chromatin immunoprecipitation; suppression of BRD4 by siRNA or JQ-1 inhibits NSCLC proliferation and migration downstream of PLEK2/PI3K/AKT signaling.\",\n      \"method\": \"Chromatin immunoprecipitation, western blot, siRNA knockdown, JQ-1 pharmacological inhibition, functional assays\",\n      \"journal\": \"Molecular biology reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP plus functional knockdown with two orthogonal perturbations (siRNA + JQ-1), single lab\",\n      \"pmids\": [\"35122599\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"CRISPR/Cas9 knockout of PIK3CD (p110δ) in GBM cells dramatically reduces PLEK2 expression (along with PAK3), placing PLEK2 downstream of PIK3CD in a pathway controlling glioma cell migration, invasion, and colony formation.\",\n      \"method\": \"CRISPR/Cas9 knockout, RT2 profiler PCR array, RNAseq, functional migration/invasion assays, in vivo tumorigenesis\",\n      \"journal\": \"Laboratory investigation\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis by complete KO with multiple functional readouts, single lab\",\n      \"pmids\": [\"35851857\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"α5-nAChR mediates nicotine-induced PLEK2 expression via STAT3 signaling in lung adenocarcinoma, and PLEK2 in turn directly interacts with CFL1 (cofilin-1) to mediate cytoskeletal remodeling and EMT in nicotine-induced cancer progression.\",\n      \"method\": \"Co-immunoprecipitation, in vivo xenograft validation, human tissue immunostaining, functional migration/invasion assays\",\n      \"journal\": \"Molecular carcinogenesis\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP for interaction plus pathway epistasis, validated in xenograft and human tissues, single lab\",\n      \"pmids\": [\"37921560\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"PLEK2 directly interacts with SPC25 (shown by co-immunoprecipitation) in lung adenocarcinoma cells, and this interaction is associated with PI3K/AKT signaling activation required for PLEK2-induced proliferation and migration.\",\n      \"method\": \"Gene expression profiling, co-immunoprecipitation, knockdown functional assays, in vivo xenograft\",\n      \"journal\": \"Cell biology international\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single Co-IP for interaction, single lab, limited mechanistic follow-up of the PLEK2–SPC25 complex\",\n      \"pmids\": [\"38894536\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"PLEK2 knockdown in gastric cancer cells reduces PD-L1 expression and promotes apoptosis; hyperthermia treatment downregulates both PLEK2 and PD-L1, partially reversing IFNγ suppression in co-cultured activated T cells.\",\n      \"method\": \"Gene knockdown (siRNA), western blot, RT-qPCR, flow cytometry, T cell co-culture assay\",\n      \"journal\": \"Gene\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single-lab knockdown study with functional readouts but no direct biochemical mechanism linking PLEK2 to PD-L1 regulation\",\n      \"pmids\": [\"38147897\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"PLEK2 promotes migration and invasion in pancreatic ductal adenocarcinoma by activating MMP1 expression and p-ERK and p-STAT3 signaling through the IL-17 pathway, as identified by RNA-seq and verified by western blot.\",\n      \"method\": \"RNA-seq, western blot, wound healing and transwell assays, in vivo xenograft, knockdown\",\n      \"journal\": \"Molecular and cellular biochemistry\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — RNA-seq pathway identification plus western blot verification, single lab, no direct biochemical mechanism for PLEK2–MMP1 link\",\n      \"pmids\": [\"39117976\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"PLEK2 (Pleckstrin-2) functions as an oncogenic scaffolding/adaptor protein that promotes cancer cell migration, invasion, and EMT through multiple mechanisms: it interacts with and protects EGFR from c-CBL-mediated ubiquitination to sustain EGFR signaling, targets SHIP2 for ubiquitin-dependent degradation to activate PI3K/AKT signaling, interacts with c-Myc to shield it from FBXW7-mediated proteasomal degradation (while c-Myc reciprocally transcribes PLEK2 in a positive feedback loop), and interacts with cofilin-1 (CFL1) to remodel the cytoskeleton; upstream, PLEK2 transcription is activated by TGF-β/Smad2/3, BRD4, ELK1, and α5-nAChR/STAT3, and PLEK2 acts downstream of PIK3CD in glioblastoma.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"PLEK2 is an oncogenic scaffolding/adaptor protein that drives cancer cell migration, invasion, and epithelial-mesenchymal transition across multiple solid tumor types [#1, #2]. It operates largely by controlling the stability and activity of signaling proteins through ubiquitination-dependent mechanisms: it binds the kinase domain of EGFR and shields it from c-CBL-mediated ubiquitination to sustain EGFR signaling [#0], and it interacts with SHIP2 to target it for ubiquitin-dependent degradation, thereby relieving inhibition of PI3K/AKT signaling and promoting EMT and invasion [#1]. PLEK2 also binds c-Myc and displaces FBXW7, preventing proteasomal degradation of c-Myc, while c-Myc reciprocally activates PLEK2 transcription to form a positive feedback loop [#6]. Convergence on PI3K/AKT signaling is a recurring theme downstream of PLEK2 [#1, #7]. PLEK2 additionally interacts with cofilin-1 (CFL1) to remodel the cytoskeleton during nicotine-induced cancer progression [#9]. PLEK2 transcription is induced by upstream regulators including TGF-\\u03b2/Smad2/3 [#3], BRD4 [#7], and \\u03b15-nAChR/STAT3 signaling [#9], and PLEK2 lies downstream of PIK3CD in glioma [#8]. Downstream effectors mediating its motility phenotypes include CCL2 [#2] and LCN2 [#4].\",\n  \"teleology\": [\n    {\n      \"year\": 2019,\n      \"claim\": \"Established a first biochemical mechanism for PLEK2 oncogenicity by showing it physically protects a receptor tyrosine kinase from degradation, explaining sustained pro-migratory signaling.\",\n      \"evidence\": \"Mass spectrometry, reciprocal Co-IP, and ubiquitination assays in gallbladder cancer cells, with RNA-seq and a mouse metastasis model identifying CCL2 as a downstream effector\",\n      \"pmids\": [\"31182136\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Does not define the structural basis of the PLEK2-EGFR kinase domain interaction\", \"Does not establish whether PLEK2 competes with c-CBL directly or acts allosterically\", \"CCL2 induction linked correlatively to EGFR signaling, not by direct biochemical step\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Showed PLEK2 can also act as a destabilizer rather than a stabilizer, targeting the lipid phosphatase SHIP2 for degradation to activate PI3K/AKT and drive EMT.\",\n      \"evidence\": \"Co-IP, ubiquitination assays, and overexpression/knockdown functional assays in NSCLC cells\",\n      \"pmids\": [\"31498891\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Does not identify the E3 ligase PLEK2 recruits to SHIP2\", \"Does not reconcile how PLEK2 protects EGFR yet degrades SHIP2 mechanistically\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Identified the upstream transcriptional driver of PLEK2, placing it within the TGF-\\u03b2 signaling axis, and defined a downstream effector for its motility phenotype.\",\n      \"evidence\": \"Luciferase reporter and ChIP assays for Smad2/3 promoter binding, plus RNA-seq and rescue experiments identifying LCN2 in oesophageal squamous cell carcinoma\",\n      \"pmids\": [\"34601488\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Does not link Smad2/3 induction of PLEK2 to a specific protein-level mechanism\", \"Mechanism connecting PLEK2 to LCN2 expression not defined\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Reinforced PLEK2 as an upstream activator of PI3K/AKT/mTOR signaling in a distinct tumor context.\",\n      \"evidence\": \"Knockdown with western blot pathway readout and xenograft in osteosarcoma cells\",\n      \"pmids\": [\"34084215\"],\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Single western-blot pathway readout for pathway placement\", \"No direct biochemical mechanism linking PLEK2 to PI3K/AKT in this context\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Provided the most rigorous mechanism: PLEK2 stabilizes the oncogenic transcription factor c-Myc by blocking FBXW7 access, and c-Myc reciprocally transcribes PLEK2, establishing a self-amplifying feed-forward loop.\",\n      \"evidence\": \"Co-IP, cycloheximide chase, ubiquitination assays, ChIP-qPCR, and luciferase reporter assays in head and neck squamous cell carcinoma\",\n      \"pmids\": [\"36002342\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Does not map the PLEK2 region required for c-Myc binding or FBXW7 displacement\", \"Does not quantify the contribution of the feedback loop to tumor maintenance in vivo\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Added a second transcriptional activator, BRD4, linking epigenetic readers to PLEK2 expression and its downstream PI3K/AKT axis.\",\n      \"evidence\": \"ChIP, siRNA and JQ-1 pharmacological inhibition with functional assays in NSCLC\",\n      \"pmids\": [\"35122599\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Does not establish whether BRD4 acts directly or via intermediary transcription factors\", \"PI3K/AKT placement downstream of PLEK2 inferred from pathway readout\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Placed PLEK2 genetically downstream of PIK3CD (p110\\u03b4), connecting it to a defined PI3K isoform-driven migration program in glioma.\",\n      \"evidence\": \"CRISPR/Cas9 knockout of PIK3CD with profiler PCR array, RNA-seq, and functional/in vivo assays in GBM cells\",\n      \"pmids\": [\"35851857\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Does not establish whether PIK3CD regulates PLEK2 transcriptionally or post-transcriptionally\", \"Direct biochemical link absent\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Connected PLEK2 to cytoskeletal remodeling through a direct interaction with cofilin-1, and embedded it in a nicotine/\\u03b15-nAChR/STAT3 induction pathway.\",\n      \"evidence\": \"Co-IP, xenograft, human tissue immunostaining, and functional assays in lung adenocarcinoma\",\n      \"pmids\": [\"37921560\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Does not define how PLEK2-CFL1 binding alters cofilin activity\", \"Single Co-IP without reciprocal mapping of interaction interface\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Extended PLEK2 function to immune evasion by linking it to PD-L1 expression and T-cell suppression in gastric cancer.\",\n      \"evidence\": \"siRNA knockdown, western blot, flow cytometry, and T-cell co-culture with hyperthermia treatment\",\n      \"pmids\": [\"38147897\"],\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"No direct biochemical mechanism linking PLEK2 to PD-L1 regulation\", \"Correlation between PLEK2 and PD-L1 not mechanistically resolved\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Reported additional candidate partners and effectors broadening the PLEK2 interaction and signaling repertoire.\",\n      \"evidence\": \"Co-IP with SPC25 in lung adenocarcinoma (PMID 38894536) and RNA-seq/western blot linking PLEK2 to MMP1 via IL-17/ERK/STAT3 in PDAC (PMID 39117976)\",\n      \"pmids\": [\"38894536\", \"39117976\"],\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"Single Co-IP for the PLEK2-SPC25 interaction without reciprocal validation\", \"No direct biochemical mechanism for the PLEK2-MMP1 link\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How a single adaptor reconciles opposing activities (stabilizing EGFR and c-Myc while degrading SHIP2) and what its structural determinants of partner selection are remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\"No structural model of PLEK2 or its interaction interfaces\", \"E3 ligase machinery PLEK2 recruits to SHIP2 unidentified\", \"Whether PLEK2's pleckstrin-homology lipid binding contributes to membrane signaling untested in this corpus\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 1, 6]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [0, 1, 6]},\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [9]}\n    ],\n    \"localization\": [],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 1, 6]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [1, 6]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [3, 6, 7]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"EGFR\", \"SHIP2\", \"MYC\", \"FBXW7\", \"CFL1\", \"SPC25\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}